Piston



Sept. 10, 1929. 5 JARDINE 1,727,647

' PISTON 7 Filed April 9, 1926 2 Sheets-Sheet l E 1 ill] TTORNEYS Patented Sept. 10, 1929.

UNITED STATES FRANK JABDINE, OF CLEVELAND, OHIO,

ASSIGNOR TO ALUMINUM COMPANY OF AMERICA, 01 PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

PISTON.

Application filed April 9, 1926. Serial No. 100,773.

This invention relates to pistons and more particularly to pistons composed of amaterial having a higher or diflerent co-efl icient of expansion than that of the cylinders 1n wh1ch they are to operate, as for instance, where aluminum or aluminum alloy pistons are used in cylinders of cast iron or the like.

As is well known, such pistons possess many desirable qualities such as lightness,

high heat conductivity and the llke. However, the difi'erences in expansion of the pistons and cylinders produce varlous difficulties and disadvantages, for example, the p1stons will either stick when hot or will slap when cold.

The principal object of my invention is to provide a piston which may be made of aluminum, aluminum alloy, or the like, which can be fitted with a very small clearance and which will maintain this clearance substantially unchanged throughout the temperature ranges met in practice, without slapping, binding, scoring of the cylinder, or undue wear in the piston itself.

These and other objects of my invention, as well as the invention itself, will be better understood from the description of practical embodiments of the invention which are illustrated in the accompanying drawings, in

which- 1* Fig. 1 is a side elevation of one form of piston embodying the invention;

Fig. 2 is a longitudinal cross section thereof on line 22 of Fig. 1;

Fig. 3 is a bottom plan view;

Fig. 4 is .a plan of the expansion controlling member or link A;

Fig. 5 isa side elevation of member A;

Figs. 6 to 10 are views corresponding to Figs. 1 to 5, respectively, of another form of piston embodying the invention.

The piston shown in Figs. 1 to 5 will first be described. It consists of a head 1 composed of a top 2 and depending annular flange 3 provided with piston ring grooves 4. Walls 5 depend from the flange and carrying the wrist pin bosses or bearings 6, the walls-and hearings being reinforced by webs 7. Below' the head is a skirt *8 which includes two thrust or hearing faces 9 and 10, spaced apart and from the head and adapted to take the angu-- lar thrust of the connecting rod. Webs 11 connect the bearing faces to the wrist pin bearings and these webs are provided with longitudinal splits spanned by bridges or culverts 12 so that the bearing faces are flexibly connected to the bearings. The bearing faces are joined below the wrist pin bearings by strap-like skirt portions 13 and these straps are rendered flexible by splits and bridges 14.

Two controlling members A are provided to control the expansion of'the skirt. As

shown, each member A consists of a hollow rectangle having horizontal top and bottom bars 15 and 16 and vertical ends 17 and 18, the horizontal bars being bent into a curve, substantially a semi-circle, as shown. One end of each controlling member is embedded in each bearing face near the center thereof and the horizontal members are embedded in the bearing faces and wrist pin bearing supporting walls, being exposed only where they span bends 12. The control members are of a material having a thermal co-eflicient of expansion substantially the same as that of the cylinder in which the piston is to operate,

such as iron or steel for pistons intended for use in cast iron cylinders, and tie the bearing faces together and so regulate the distance therebetween while the flexible bends allow for the expansion of the aluminum.

The piston is conveniently made as follows :First, the controlling members A are made as by being stamped from sheet steel. These are then placed in a mold and the remainder of the piston, of aluminum alloy or the like cast simultaneously and integrally around these controlling members. After this the piston may be machined to proper dimensions.

In Figs. 6 to 10 is illustrated a piston very similar to that above described. The substantially radial webs 11' flexibly join the thrust or bearing faces 9' and 10' to the wrist pin bearings 6'. 'The strips 13 which join the bearing faces are split at 13 and the splits spanned by resilient arcuate bridges or culverts-l4' to allow for expansion of the metal. Two control members B of iron, steel or other material having a co-eflicient of expansion near, that of the cylinder join the bearing walls. These members each-consist of top and bottom horizontal bars 15 and 16 and ends 17 and 18. The horizontal bars are bent at their ends to conform to the curvature of the bearing faces while their central portions are straight, as shown in Fig. 9. The curved end portions of these members are embedded in the bearing faces while the straight intermediate portions extend chordally thereibetween and are for the most part expose My invention may obviously be incorpo rated in many other forms and modifications, and I do not, therefore, limit myself to the two forms shown, but claim all embodiments of the invention which come with in the scope of the appended claims.

I claim:

v 1. A piston having a head, wrist pin bearings depending therefrom, a skirt comprising two spaced bearing faces connected together below the wrist pin bearings by straps having re-entrant bends said bearing faces connected to the wrist pin bearings by supporting straps haying re-entrant bends, and means controlling the distance between the bearing faces.

2. A piston having a skirt composed of two spaced thrust faces and tie members controlling the distance between the said faces, each tie member having its central portion between the thrust faces and one end embedded in each face and extending within the same from one edge substantially to the center thereof. e

3. A piston having a skirt composed of two spaced bearing faces resiliently connected together and to the piston head, vertically disposed links connecting the bearing faces together and controlling the distance between them, the ends of the links being embedded in the bearing faces near their centers and the links extending around and embedded in the bearing faces to the edges thereof.

, 4. A piston comprising a head, walls depending therefrom and carrying wrist pin bearings, a skirt having bearing faces intermediate said wrist pin bearings, flexible webs joining said bearing faces to said depending walls, flexible webs connecting saidbearing faces together below said Wrist, pinbearings all made of a material having a high co-efficient of expansion, controlling members of a material having a lower co-efiicient of expansion, said members having upper and lower horizontal bars em- .bedded at their centers in the depending walls and vertical end bars embedded in the bearing faces near the centers thereof.

5. A piston comprising a head, two walls depending therefrom and carrying wrist pin bearings, a skirt having two bearing faces, intermediate said wrist-pin bearings, flexible V webs joining said bearing faces to said depending walls, flexible straps joining said bearing faces below said wrist pin bearings, all of a material having a relatively high coefficient of expansion, and two expansion controlling members of a material having a lower co-efiicient of expansion, said members eachand depending walls and between the opposite bearing faces, all of aluminum alloy, and two steel expansion controlling members each being a vertical, curved, hollow rectangle with its ends embedded in the bearing faces near thecenters thereof and its top and bottom members having their centers embedded in one of the depending walls.

7. A piston having a skirt with spaced bearing faces and a vertically disposed link at each side of the skirt having one end embedded in each bearing face near its center and its sides extending chordallybetween the bearing faces.

In testimonv whereof I hereunto afiix my signature this 5th day of April, 1926.

FRANK J ARDIN E. 

